Method for manufacturing rotor

ABSTRACT

An exemplary method for manufacturing a rotor is disclosed. A fixture is firstly made. The fixture includes a base, a column extending upwardly from the base, and an annular protrusion extending upwardly from the column. A slot is defined in the column. A shaft is inserted in the slot. A hub is made and disposed on a top face of the annular protrusion. The hub includes a cover and a sidewall extending downwardly from the cover. The shaft contacts a center of the cover. A laser beam is used to illuminate the center of the cover to thereby weld the shaft with the cover.

BACKGROUND

1. Technical Field

The disclosure generally relates to a method for manufacturing a rotor and, particularly, to a method for manufacturing a rotor of an impeller.

2. Description of Related Art

With the continuing development of electronic technology, electronic components are made to have smaller sizes and higher frequencies. However, issues of heat dissipation are also raised accordingly. In order to cool the electronic components, heat dissipation devices, such as fans, are used to dissipate heat from the electronic components.

The rotor of a typical fan includes a hub, a plurality of blades formed on an outer circumferential face of the hub, a magnetic ring received in the hub, and a shaft fixed to a center of the hub. Generally, there are two different ways for fixing the shaft to the hub. One way is to use a sleeve enclosing an end of the shaft, and then insert the shaft together with the sleeve into a hole of the hub by riveting. However, the sleeve needs to be individually manufactured and machined in addition to the shaft and the hub. Thus, the manufacture of the fan is complicated and costly. Another way is to dispose the shaft and the hub in a mold and then use insert-molding to join the shaft with the hub under a high temperature. However, the process of the insert-molding is also complicated, and may cause damage to the hub under such a high temperature.

What is needed, therefore, is a means which can address the limitations described.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the various views.

FIG. 1 shows a rotor and a fixture used in a method in accordance with an embodiment of the present disclosure.

FIG. 2 is an inverted view of the rotor and the fixture of FIG. 1.

FIG. 3 is similar to FIG. 1, but showing the rotor disposed on the fixture.

FIG. 4 is a cross section of the rotor and the fixture of FIG. 3, taken along a line IV-IV thereof.

FIG. 5 is similar to FIG. 4, but showing a shaft inserted in a hub of the rotor.

DETAILED DESCRIPTION

Referring to FIGS. 1-2, a rotor 100 and a fixture 200 used in a method in accordance with an embodiment of the present disclosure are shown. The rotor 100 includes a hub 30 and a shaft 40 disposed below the hub 30. The hub 30 includes a cover 31 and a sidewall 33 extending downwardly from a circumferential periphery of the cover 31.

The cover 31 includes a disk 310, a ring 320 extending downwardly from a circumferential periphery of the disk 310, and a flange 330 extending outwardly and horizontally from a bottom of the ring 320. The disk 310 is located higher than the flange 330. The disk 310 is parallel to the flange 330. The sidewall 33 connects an outer circumferential periphery of the flange 330. A bottom face of the disk 310 is flat without any hole defined therein. The shaft 40 is located at a center of a bottom face of the disk 310.

The fixture 200 includes a base 21, a column 22 extending upwardly from a top face of the base 21, and an annular protrusion 23 protruding upwardly from a top face of the column 22. The base 21 has a diameter larger than that of the column 22. The column 22 has a height larger than that of the base 21. The annular protrusion 23 has an outer diameter less than the diameter of the column 22. The annular protrusion 23 has a height less than that of the column 22. The annular protrusion 23 surrounds a cavity 230 therein. A slot 231 is defined in a bottom of the cavity 230. The slot 231 extends along a height direction of the column 22. The slot 231 has a depth less than a length of the shaft 40.

Also as shown in FIGS. 3-4, in assembly of the shaft 40 to the hub 30, the shaft 40 and the hub 30 are firstly disposed on the fixture 200. The shaft 40 is received in the slot 231 with a top face thereof leveled with a top face of the annular protrusion 23. The bottom face of the disk 310 of the hub 30 is disposed on the top face of the annular protrusion 23 such that a center of the bottom face of the disk 310 contacts the top face of the shaft 40. The flange 330 is located above the top face of the column 22 with an air gap 232 presenting between a bottom face of the flange 330 and the top face of the column 22. The sidewall 33 surrounds the column 22 with an inner circumferential face of the sidewall 33 contacting an outer circumferential face of the column 22. Thus, the shaft 40 and the hub 30 are positioned relative to each other by the fixture 200.

A laser beam is then used to weld the shaft 40 to the hub 30. The laser beam has a relatively high energy at a focus thereof so that an object disposed on the focus of the laser beam will be melted. In this embodiment, the laser beam is projected to a center of the hub 30 to melt the center of the hub 30. The top face of the shaft 40 then joins the melted center of the hub 30. After the center of the hub 30 is cooled to harden, the top face of the shaft 40 is firmly fixed to the center of the hub 30. Alternatively, as shown in FIG. 5, a through hole 311 may also be defined in the center of the hub 30 beforehand, the shaft 40 is inserted to the through hole 311 with a top face of the shaft 40 leveled with a top face of the disk 310. The laser beam can weld an outer circumferential face of the shaft 40 with an inner circumferential face of the through hole 311, thereby fixing the shaft 40 to the hub 30.

Heat generated during laser welding is low, whereby the shaft 40 and the hub 30 will not be significantly affected or even damaged by a high temperature. Furthermore, the laser-welding process of the shaft 40 to the hub 30 is relatively simple. Therefore, the manufacture of the rotor 100 is convenient and time-saving. In addition, no connecting element (such as a sleeve) is required for joining the shaft 40 to the hub 30, whereby the cost of the rotor 100 is reduced accordingly.

It is to be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

What is claimed is:
 1. A method for manufacturing a rotor, comprising: making a fixture defining a slot therein; disposing a shaft in the slot of the fixture; making and disposing a hub on the fixture such that the shaft contacts a central area of the hub; welding the shaft to the central area of the hub by a laser beam.
 2. The method of claim 1, wherein the hub comprises a cover and the hub is disposed on the fixture such that the cover contacts a top face of the fixture.
 3. The method of claim 2, wherein the hub comprises a sidewall and the hub is disposed on the fixture such that the sidewall surrounds an outer circumferential face of the fixture.
 4. The method of claim 3, wherein the sidewall extends downwardly and perpendicularly from the cover.
 5. The method of claim 3, wherein the cover comprises a disk spaced from the sidewall.
 6. The method of claim 5, wherein the cover comprises a ring extending downwardly from a circumferential periphery of the disk, and a flange extending outwardly from the ring, the sidewall connecting the flange.
 7. The method of claim 6, wherein the disk is parallel to the flange and located higher than the flange.
 8. The method of claim 6, wherein the fixture comprises a column and an annular protrusion extending upwardly from a top face of the column, and the hub is disposed on the fixture such that the disk of the hub is disposed on a top face of the annular protrusion.
 9. The method of claim 8, wherein the sidewall of the hub contacts an outer circumferential face of the column of the fixture.
 10. The method of claim 8, wherein the hub is disposed on the fixture such that the flange of the cover is located above the top face of the column with an air gap between a bottom face of the flange and the top face of the column.
 11. The method of claim 8, wherein the fixture further comprises a base supporting the column thereon, and the base has a diameter larger than a diameter of the column.
 12. The method of claim 11, wherein the base has a height less than a height of the column.
 13. The method of claim 8, wherein the annular protrusion has an outer diameter less than the diameter of the column, and a height less than a height of the column.
 14. The method of claim 8, wherein the annular protrusion surrounds a cavity therein, and the slot is defined in a bottom of the cavity.
 15. The method of claim 8, wherein a top face of the shaft is leveled with the top face of the annular protrusion of the fixture during the step of disposing the shaft in the slot of the fixture.
 16. The method of claim 5, wherein a top face of the shaft is in contacting with a center of a bottom face of the disk of the hub during the step of disposing the hub on the fixture.
 17. The method of claim 5, wherein the hub defines a through hole at a center of the disk, and the shaft is inserted to the through hole during the step of disposing the hub on the fixture.
 18. The method of claim 17, wherein the hub is disposed on the fixture such that a top face of the shaft is leveled with a top face of the disk.
 19. The method of claim 17, wherein the shaft is welded to the hub such that a circumferential face of the shaft is fixed to an inner circumferential face of the through hole of the hub. 